Single-reel type tape cartridge

ABSTRACT

In a single-reel type tape cartridge, a coupling portion of a leader tape includes a pair of winding pieces disposed at opposite sides of a cutout and each winding piece includes a base portion and a turnover portion wound around a pin of a leader member so as to be ultrasonically welded to the base portion. An anvil for supporting the coupling portion of the leader tape has a pair of anvil faces each having a width smaller than that of the turnover portion and ultrasonic welding of the turnover portion to the base portion is performed by supporting the coupling portion on the anvil faces. The turnover portion is divided into a completely welded area having a width substantially equal to that of each of the anvil faces and an incompletely welded area disposed outside each of opposite side edges of the completely welded area.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a single-reel type tape cartridge inwhich a leader member is coupled with a leading edge of a tape. Theleader member is provided for drawing out the tape to a tape drivemechanism and is coupled with a leader tape joined to a leading edge ofa magnetic tape.

2. Description of the Prior Art

In order to couple the leader member with the leader tape, it is knownfrom, for example, Japanese Patent Laid-Open Publication No. 2002-324377that a cutout is formed at a widthwise central location of a couplingportion of the leader tape so as to define a pair of winding pieces atopposite sides of the cutout in the coupling portion and the windingpieces are wound around a pin of the leader member and turned over tothe leader tape so as to be attached to the leader tape by ultrasonicwelding. By rounding lateral side edges of a welding hone depressedagainst the winding pieces, one lateral edge of each winding pieceadjacent to its distal edge and the other lateral edge of each windingpiece adjacent to the pin of the leader member are subjected to weldingto a more scatterable degree than other weld zones so as to preventconcentration of loads on the welded lateral edges of each winding piecesuch that the leader tape is prevented from being fractured at thewelded lateral edges of each winding piece.

Meanwhile, fused resin may ooze out of peripheral edges of the weldedwinding pieces so as to be solidified. In order to prevent dropout dueto drop of the solidified resin in the tape drive mechanism, it is knownfrom, for example, Japanese Patent Laid-Open Publication No. 2001-357658that an external shape of a welded portion is made slightly smaller thana shape of the peripheral edge of each winding piece so as to form anunwelded portion along the peripheral edge of each winding piece. Awidth of the unwelded portion is set at not less than 0.1 mm.

In the coupling construction of the leader member in the first prior artdocument referred to above, since the one lateral edge of each windingpiece adjacent to its distal edge and the other lateral edge of eachwinding piece adjacent to the pin of the leader member are subjected towelding to a more scatterable degree than other weld zones, loadsconcentrated on the welded lateral edges can be scattered widely.However, from a microscopic viewpoint, as welding is performed morescatteredly, load is more likely to be concentrated on welded spots, sothat the welded spots readily undergo separation and breakage and thus,it is impossible to avoid gradual drop of welding strength of the weldedspots. Since a droplike space for winding the winding pieces around thepin increases by an amount of separation of the welded spots, the pinbecomes loose in the coupling portion of the leader tapedisadvantageously.

Meanwhile, in the coupling construction of the leader member in thesecond prior art document referred to above, since the unwelded portionis formed along the peripheral edge of each winding piece, ooze of thefused resin can be prevented. However, since the width of the unweldedportion is small, it is necessary to accurately position a press face ofthe welding hone relative to the winding pieces and thus, therebyresulting in such an inconvenience as time-consuming and troublesomewelding operation.

SUMMARY OF THE INVENTION

Accordingly, an essential object of the present invention is to providea single-reel type tape cartridge in which since a winding piece of aleader tape is wound around a pin of a leader member so as to be weldedto the leader tape securely at a high welding strength by positivelypreventing ooze of fused resin out of a peripheral edge of the weldedwinding piece, reliability of a coupling section between the leader tapeand the leader member can be upgraded.

Another important object of the present invention is to provide asingle-reel type tape cartridge in which by restraining deterioration ofmaterial of opposite side edges of the winding piece and the leader tapeattached to each other upon thermal welding of the winding piece,fracture of the leader tape from a welded edge of the winding piece canbe prevented positively.

In order to accomplish these objects of the present invention, asingle-reel type tape cartridge according to the present inventionincludes a leader tape having a coupling portion disposed at its leadingedge, a leader member having a pin and an anvil for supporting thecoupling portion of the leader tape. The coupling portion is woundaround the pin and turned over to the leader tape so as to be attachedto the leader tape by ultrasonic welding and includes a pair of windingpieces spaced away from each other by an elongated cutout formed at acentral portion of an end of the leader tape. Each of the winding piecesincludes a base portion disposed at its base end portion and a turnoverportion wound around the pin and turned over to the base portion so asto be attached to the base portion by ultrasonic welding. The anvil hasa pair of anvil faces each having a width smaller than that of theturnover portion and ultrasonic welding of the turnover portion to thebase portion is performed by supporting the coupling portion on theanvil faces. A completely welded area having a width substantially equalto that of each of the anvil faces is formed from a center to a vicinityof opposite side edges of the turnover portion and an incompletelywelded area is formed between each of opposite side edges of thecompletely welded area and each of the opposite side edges of theturnover portion.

BRIEF DESCRIPTION OF THE DRAWINGS

These objects and features of the present invention will become apparentfrom the following description taken in conjunction with the preferredembodiments thereof with reference to the accompanying drawings inwhich:

FIG. 1 is a top plan view showing a configuration in which a couplingportion of a leader tape is welded to the leader tape via a pin of aleader member in a single-reel type tape cartridge according to a firstembodiment of the present invention;

FIG. 2 is an enlarged view of a portion P1 in FIG. 1;

FIG. 3 is a top plan view showing an internal structure of thesingle-reel type tape cartridge of FIG. 1;

FIG. 4 is a front elevational view showing an operational state of thesingle-reel type tape cartridge of FIG. 1, in which the leader member isdrawn out of a cartridge casing;

FIG. 5 is a vertically sectional side elevational view showing a weldingstate of the coupling portion of the leader-tape of FIG. 1;

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is an enlarged view of a portion P2 in FIG. 6;

FIG. 8 is a front elevational view showing a developed state of thecoupling portion of FIG. 1;

FIG. 9 is a top plan view showing an anvil employed in a single-reeltype tape cartridge according to a second embodiment of the presentinvention; and

FIG. 10 is an enlarged view of a portion P3 in FIG. 9.

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like reference numeralsthroughout several views of the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention are described withreference to the drawings.

First Embodiment

FIGS. 1 to 8 show a single-reel type tape cartridge according to a firstembodiment of the present invention. In FIGS. 3 and 4, the single-reeltype tape cartridge includes a rectangular boxlike casing 1 formed byupper and lower casings 1 a and 1 b which confront each other so as tobe bonded to each other. A tape 3 for recording magnetic signals thereonis wound into a single reel 2 disposed inside the cartridge casing 1. Atape window 4 opens on a front wall of the cartridge casing 1 and isselectively opened and closed by a pivotally movable door 5. The door 5is normally urged towards a closed position of the tape window 4 by aspring and is locked at the closed position by a locking mechanism (notshown). Reel locking pawls 6 and 7 are, respectively, provided at twoopposed inner corners of the cartridge casing 1 and are brought intoengagement with gear teeth formed on an outer circumference of the reel2 so as to hold the reel 2 immovably. A switching piece 8 for preventingerroneous erasure is provided on an inner face of a rear wall of thecartridge casing 1.

In order to enable a catch member of a tape drive mechanism toautomatically catch the tape 3 wound into the reel 2, a leader tape 10is attached to a leading edge of the tape 3 and a leader member 11 iscoupled with an end portion of the leader tape 10. The leader member 11is formed into a substantially U-shaped frame including a pin 12 made ofstainless steel and a pair of engagement arms 13 provided at oppositeends of the pin 12, respectively.

As shown in FIGS. 1 and 2, the pin 12 is formed by a thin round rod andhas a locking rod 12 a disposed at its central portion and a pair ofwinding rods 12 b disposed at opposite sides of the locking rod 12 a,respectively. Each of the winding rods 12 b is slightly smaller indiameter than the locking rod 12 a and an anchor portion 12 c is formedat a distal end of each of the winding rods 12 b. A pair of stepportions 14 for positioning the leader tape 10 are, respectively, formedat opposite ends of the locking rod 12 a due to a difference in diameterbetween the locking rod 12 a and the winding rods 12 b and a half of thedifference is set at not less than a half of a thickness of the leadertape 10. The anchor portion 12 c is tapered towards the locking rod 12 aand is attached to the engagement arm 13 through insertion so as toprevent separation of the engagement arm 13 and the pin 12 from eachother such that the engagement arm 13 and the pin 12 are prevented frombeing rotated relative to each other.

The engagement arm 13 is formed by an elongated plastic molded itemcurved convexly towards exterior of the cartridge casing 1 and has anengagement slot 16 formed on its inner side face and a guide face 17inclined downwardly towards the engagement slot 16. The catch member ofthe tape drive mechanism is brought into engagement with the opposedengagement slots 16 of the upper and lower engagement arms 13 and isoperated so as to draw the tape 3 out of the cartridge casing 1. A mouth18 is formed at a longitudinally inner end of the engagement slot 16.

The leader tape 10 is formed by an elastic and hard plastic sheet madeof, for example, polyethylene terephthalate or polybutyleneterephthalate and a coupling portion 20 is formed at a leading edge ofthe leader tape 10. The coupling portion 20 is coupled with the pin 12so as to be made integral with the leader member 11. The couplingportion 20 is constituted by a pair of winding pieces 22 which arespaced away from each other by an elongated cutout 21 formed at acentral portion of an end of the leader tape 10. As shown in FIG. 1, awidth H of the cutout 21 is so set as to be slightly larger than alength of the locking rod 12 a of the pin 12. In FIG. 8 showing adeveloped state of the coupling portion 20, each of the winding pieces22 is formed by a base portion 23 disposed at its base end portion andhaving a constant width and a tapered turnover portion 24 extendingcontinuously from the base portion 23. Opposite corners of a distal endof the turnover portion 24 are rounded smoothly.

The leader tape 10 and the leader member 11 are coupled with each otheras follows. As shown in FIGS. 1, 2 and 5, the turnover portion 24 iswound around each of the winding rods 12 b of the pin 12 and turned overto the base portion 23. In a state where there is a slight play betweenthe winding piece 22 and the winding rod 12 b, the turnover portion 24is attached to the base portion 23 by ultrasonic welding. At this time,the present invention is characterized in that ultrasonic welding of theturnover portion 24 is performed by using an improved anvil 26 and awelding hone 27.

More specifically, as shown in FIGS. 6 and 7, a central portion andopposite side portions of one end of an upper face of the anvil 26 areremoved as a central recess 29 and a pair of opposite side recesses 29,respectively such that a pair of rectangular anvil faces 28 each forsupporting the base portion 23 are defined between the central recess 29and one of the opposite side recess 29 and between the central recess 29and the other of the opposite side recesses 29, respectively. As shownin FIGS. 1 and 2, a width B2 of the anvil face 28 is so set as to besmaller than a maximum width B1 of the turnover portion 24. In thisembodiment, the width B2 of the anvil face 28 is set at 70% of themaximum width B1 of the turnover portion 24 but may range from 65% to75% of the maximum width B1 of the turnover portion 24. After the leadermember 11 has been positioned and held by a jig (not shown), the baseportion 23 and the turnover portion 24 held in contact with each otherare placed on the anvil face 28 and gripped between a press face 27 a ofthe welding hone 27 and the anvil face 28 of the anvil 26. By performingultrasonic vibrations of the welding hone 27 in this state, the turnoverportion 24 and the base portion 23 are welded to each other.

In case ultrasonic welding is performed by using the anvil face 28narrower than the turnover portion 24 as described above, a completelywelded area W1 having a width equal to the width B2 of the anvil face 28is formed from a center to a vicinity of opposite side edges of theturnover portion 24 as shown by coarse hatching in FIG. 2. On the otherhand, in opposite side portions of a contact area between the turnoverportion 24 and the base portion 23, which project out of opposite sideedges of the anvil face 28, a pair of incompletely welded areas W2having welding degree lower than that of the completely welded area W1are formed as shown by fine hatching in FIG. 2 because frictional heatobtained by the welding hone 27 becomes smaller as a location on theturnover portion 24 becomes more distant from the anvil face 28. Thus,fused resin pushed out of the completely welded area W1 flows to theincompletely welded areas W2 so as to bond the turnover portion 24 tothe base portion 23 also in the incompletely welded areas W2. As aresult, material deterioration of the opposite side edges of theturnover portion 24 and the base portion 23 can be eliminated while theturnover portion 24 is securely welded to the base portion 23.Therefore, it is possible to positively prevent such a phenomenon thatfracture of the leader tape 10 starts from the opposite side edges ofthe turnover portion 24 and the base portion 23 upon thermal welding ofthe winding pieces 22. It is also possible to prevent the fused resinfrom oozing out of the opposite side edges of the base portion 23.

In a state where the coupling portion 20 has been coupled with the pin12, the lower edge of the upper winding piece 22 and the upper edge ofthe lower winding piece 22 are, respectively, positioned by the upperand lower step portions 14 of the locking rod 12 a as shown in FIGS. 1and 2 and thus, the coupling portion 20 of the leader tape 10 can beregulated from shifting upwardly or downwardly from a predeterminedposition. Meanwhile, since a slight gap is formed between the pin 12 andthe winding pieces 22, the leader member 11 and the leader tape 10 areallowed to be rotated relative to each other.

In order to hold and fix the leader member 11 at a predetermined waitingattitude when the tape cartridge is not in use, a locking member 31 isdisposed in the cartridge casing 1 so as to confront the tape window 4and upper and lower arm supports 32 for supporting the upper and lowerengagement arms 13 are provided adjacent to the locking member 19 in theupper and lower casings 1 a and 1 b, respectively as shown in FIG. 3.When the upper and lower engagement arms 13 are, respectively, supportedby the upper and lower arm supports 32 and the locking rod 12 a isgripped by the locking member 31, the leader member 11 can be held at aproper waiting attitude at all times. In addition, even if the tape 3 isslackened at this time, the previously positioned waiting attitude ofthe leader member 11 can be held against drop impact. Meanwhile, lockingof the locking member 31 is released by inserting a pin from outside ofthe cartridge casing 1.

Second Embodiment

FIGS. 9 and 10 show a pair of anvil faces 28′ of an anvil 26′ employedin a single-reel type tape cartridge according to a second embodiment ofthe present invention. In the first embodiment, the anvil face 28 isformed into a rectangular shape as described above. However, in thesecond embodiment, a base portion of the anvil face 28′ is expanded intoa trapezoidal shape so as to increase a region of the completely weldedarea W1 at the distal end of the turnover portion 24. Since otherconstructions of this single-reel type tape cartridge of the secondembodiment are similar to those of the single-reel type tape cartridgeof the first embodiment, the description is abbreviated for the sake ofbrevity.

In the foregoing embodiments, the turnover portion 24 is tapered towardsits distal end but is not required to be tapered towards its distal end.The turnover portion 24 may be at least formed gradually smaller towardsits distal end. If necessary, an almost whole portion of the turnoverportion 24 may be formed into a rectangular shape having a widthslightly smaller than that of the base portion 23 such that the turnoverportion 24 is made continuous with the base portion 23 smoothly.Furthermore, the anvil face 28 may be formed gradually smaller towardsits base portion so as to make a smaller similar figure of the turnoverportion 24 such that the incompletely welded areas W2 have a constantwidth.

Hereinafter, marked effects gained in the single-reel type tapecartridge of the present invention are described. Firstly, thecompletely welded area W1 having the width substantially equal to thatof the anvil face 28 is formed in the turnover portion 24, while theincompletely welded area W2 is formed between each of the opposite sideedges of the completely welded area W1 and each of the opposite sideedges of the turnover portion 24. In the incompletely welded areas W2projecting out of the opposite side edges of the anvil face 28, sincesufficient frictional heat cannot be obtained, welding degree of abonding face between the turnover portion 24 and the base portion 23drops further as a location on the bonding face becomes more distantfrom the anvil face 28. Thus, the fused resin pushed out of thecompletely welded area W1 flows to the incompletely welded areas W2 soas to bond the turnover portion 24 to the base portion 23 also in theincompletely welded areas W2. As a result, since transfer of frictionalheat to the opposite side edges of the turnover portion 24 and the baseportion 23 is restricted while the turnover portion 24 is securelywelded to the base portion 23, material deterioration of the oppositeside edges of the turnover portion 24 and the base portion 23 can berestrained. Therefore, in the single-reel type tape cartridge of thepresent invention, since the turnover portion 24 can be securelyattached to the base portion 23 at a high welding strength, not onlyreliability of a coupling section between the leader member 11 and theleader tape 10 can be upgraded but material deterioration of theopposite side edges of the turnover portion 24 and the base portion 23upon thermal welding of the winding piece 22 can be restrained. Hence,fracture of the leader tape 10 from the opposite side edges of the baseportion 23 and the turnover portion 24 can be prevented positively.Since the fused resin which has oozed out of the completely welded areaW1 is received by the incompletely welded areas W2, it is also possibleto prevent ooze of the fused resin out of the opposite side edges of thebase portion 23.

Secondly, since the turnover portion 24 is formed gradually smallertowards its distal end such that the incompletely welded area W2 isformed gradually smaller towards its distal end along each of theopposite side edges of the turnover portion 24, a length of a weldingsection of the turnover portion 24 along the pin 12, on which weldingsection an external load is likely to be concentrated, namely, a sum ofa length of a welding section of the completely welded area W1 along thepin 12 and a length of welding sections of the incompletely welded areasW2 along the pin 12 can be made large, so that reliability of thecoupling section between the leader member 11 and the leader tape 10 canbe further upgraded by increasing welding strength between the turnoverportion 24 and the base portion 23.

Thirdly, since the width B2 of the completely welded area W1 is set atabout 70% of the maximum width B1 of the turnover portion 24, a surpluswidth of about 15% of the maximum width B1 of the turnover portion 24 isleft at each of opposite sides of the completely welded area W1 in theturnover portion 24. Hence, even if accuracy of positioning the baseportion 23 relative to the anvil face 28 is low, ooze of the fused resinout of the opposite side edges of the base portion 23 can be preventedby securely welding the turnover portion 24 to the base portion 23.Therefore, in contrast with conventional welding in which a press faceof a welding hone is required to be accurately positioned relative tothe winding pieces, winding operation can be easily performed rapidly,thereby resulting in rise of production efficiency of the tapecartridge.

1. A single-reel type tape cartridge comprising: a leader tape whichincludes a coupling portion disposed at its leading edge; a leadermember which includes a pin; and an anvil for supporting the couplingportion of the leader tape; wherein the coupling portion is wound aroundthe pin and turned over to the leader tape so as to be attached to theleader tape by ultrasonic welding and includes a pair of winding piecesspaced away from each other by an elongated cutout formed at a centralportion of an end of the leader tape; wherein each of the winding piecesincludes a base portion disposed at its base end portion and a turnoverportion wound around the pin and turned over to the base portion so asto be attached to the base portion by ultrasonic welding; wherein theanvil has a pair of anvil faces each having a width smaller than that ofthe turnover portion and ultrasonic welding of the turnover portion tothe base portion is performed by supporting the coupling portion on theanvil faces; wherein a completely welded area having a widthsubstantially equal to that of each of the anvil faces is formed from acenter to a vicinity of opposite side edges of the turnover portion andan incompletely welded area is formed between each of opposite sideedges of the completely welded area and each of the opposite side edgesof the turnover portion.
 2. The single-reel type tape cartridge asclaimed in claim 1, wherein the turnover portion is formed graduallysmaller towards its distal end such that the incompletely welded area isformed gradually smaller towards its distal end along each of theopposite side edges of the turnover portion.
 3. The single-reel typetape cartridge as claimed in claim 1, wherein a width of the completelywelded area is set at about 70% of a maximum width of the turnoverportion.
 4. The single-reel type tape cartridge as claimed in claim 2,wherein a width of the completely welded area is set at about 70% of amaximum width of the turnover portion.